1. Field of the Invention
This invention relates to a high frequency heating apparatus using a microcomputer controlled inverter and, more particularly, to a high frequency heating apparatus which can be suitably applied to a microwave oven or an electromagnetic cooking device using high frequency heating.
2. Description of the Related Art
Recently, a cooking device using an inverter for driving power supply has been known as a typical example of cooking devices using high frequency heating, e.g., microwave ovens using a magnetron as a heating source.
More specifically, such a microwave oven employs an inverter which enables the oven to continuously adjust a heating output. In addition, by using a high frequency driving power source, a high-voltage transformer and a high-voltage capacitor for driving a magnetron can be reduced in weight and size.
In spite of the above-described advantages, a microwave oven using such an inverter has a complicated arrangement, and hence the cost is inevitably increased due to the following reason.
In a conventional technique, in order to perform switching of the inverter, this microwave oven requires, for example, (1) an oscillator for generating a sawtooth signal, (2) a pulse width modulator (PWM) for PWM-modulating an output from the oscillator by using an output setting signal, and (3) a driver for ON/OFF-driving a switching element of the inverter in accordance with an output from the pulse width modulator.